Abdominal pain is the most common gastrointestinal symptom for which medical evaluation is sought. It is a nonspecific, unpleasant sensation that can be associated with a multitude of conditions originating both within and outside the abdomen. Causes may range from common normal physiologic processes to life-threatening emergencies. There are many factors that contribute to the sensation and perception of pain, including underlying pathology, psychosocial disorders, and an individual’s pain tolerance. Thus, abdominal pain is one of the most complex complaints that clinicians encounter.

The sensation of pain is produced by mechanical stimuli, chemical stimuli, or a combination of both. The most common mechanical stimulus is stretch. There are stretch receptors located in the muscular layer of the hollow organs (gastrointestinal, urinary, and biliary tracts), mesentery (membranous attachment of intra-abdominal organs to the posterior abdominal wall), and in the capsule (membranous outer...